One of the nation’s oldest marathons will bring more than 1,000 runners to Atlantic City on Sunday morning. The Atlantic City Marathon is starting at 8 a.m. Sunday along with a half-marathon. Two related races, covering 3.1 miles and 6.2 miles, are taking place on Saturday. About 10 miles of the 26.2-mile marathon will be run on the city’s historic boardwalk according to Genia Bittner, race director for the Atlantic City Marathon Race Series. As of 10 a.m. Friday, 3,200 had signed up for the races, including 1,100 marathon runners, Bittner said. Those running the marathon include Ray Pinney, w…